Nibali, who captured his fourth stage of the Tour, stuck out his tongue, tapped his chest, and raised a fist skyward as he finished the 145.5-kilometer (90-mile) leg more than a minute ahead of Thibaut Pinot of France, who was second. Rafal Majka of Poland, in third, was another two seconds back.

The remarkable effort by Nibali, who was on track to become the first Italian to win the Tour since Marco Pantani in 1998, essentially made the real race drama about who will join him on the podium on the Champs-Elysees on Sunday.

While three stages left, Friday's is mostly flat and unlikely to allow a breakaway rider to gain time. The last real challenge will be Saturday's individual time trial, but Nibali's lead is so big -- 7:10 ahead of Pinot and 7:23 ahead of France's Jean-Christophe Peraud -- that it would take a disaster for him to lose the yellow jersey before Sunday.

The race for second heated up: Alejandro Valverde of Spain lost crucial seconds on the last climb and fell from second overall to fourth. But he is considered the strongest time-trial rider among the three main aspirants for the podium, including Pinot and Peraud.

After setting off from Pau, riders tackled the famed Tourmalet pass -- the highest Pyrenean peak on this Tour -- before heading up to Hautacam ski station. Both climbs are among the toughest in professional cycling.